Time-controlled fuel pump unloading means for pressure-atomizing oil burners



1953 J. A. LOGAN ET AL 2,661,795

TIME-CONTROLLED FUEL PUMP UNLOADING MEANS FOR PRESSURE-ATOMIZING OILBURNERS Filed May 21, 1952 4 Sheets-Sheet l Izzy].

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ATTORNEYS LOGAN ET AL 2,661,795

Dec. 8, 1953 TIME-CONTROLLED FUEL. PUMP UNLOADING MEANS FORPRESSURE-ATOMIZING OIL. BURNERS 4 Sheets-Sheet 2 Filed May 21, 1952 i6if J7 g J5 \nunn 2 26 g a;

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Dec. 8, 1953 A LOGAN ET AL 2,661,795

J.. TIME-CONTROLLED FUEL PUMP UNLOADING MEANS FOR PRESSURE-ATOMIZING OILBURNERS Filed May 21, 1952 4 Sheets-Sheet 3 |NVENTOR., fisqp i [aged M27Zayerze KfaaaZlae,

LZWrM ATTORNEYS Dec. 8, 1953 J. A. LOGAN ET AL 2,661,795

TIME-CONTROLLED FUEL. PUMP UNLOADING MEANS FOR PRESSURE-ATOMIZING OILBURNERS Filed May 21, 1952 4 Sheets-Sheet 4 INVENTOR5.

Patented Dec. 8, 1953 TIME-CONTROLLED FUEL PUMP UNLOAD- ING MEANS FORPRESSURE-ATOMIZING OIL BURNERS Joseph A. Logan, Hadley, and Eugene V.Lavallee, South Hadley Falls, Mass., assignors to Gilbert & BarkerManufacturing Company,

West

Springfield, Mass, a corporation of Massa chusetts Application May 21,1952, Serial N0. 289,058

This invention relates to improvements in oil burners of thepressure-atomizing type, such as are adapted for house heating serviceand are started and stopped, usually by automatic thermostat control,many times each day during the heating season.

The ordinary burner of this type has an airsupply fan of anon-positively-acting type and an oil-supply pump of a positively-actingtype, both driven by an electric motor and moving synchronouslytherewith at all times. A cutoff valve is interposed in the pipe betweenthe pump and nozzle, opening only after the desired high atomizingpressure has been established. Such a burner has the disadvantage thatefficient combustion, during the normal running interval of each cycleof operation of the burner, cannot be had without causing ineflicientcombustion and resulting smoky operation, during the starting andstopping intervals of the burner cycle, when the moving parts arerespectively accelerating and decelerating. In the starting interval,the fan, being non-positive in action, does not have time to establishthe normal rate of air flow past the atomizing nozzle before the oilpump, which is positive in action and usually has a pumping rateconsiderably in excess of that at which oil is consumed, has establishedfull atomizing pressure, causing atomized oil to be emitted from thenozzle before air flow is available at a suificient rate-to result ingood combustion. In the stopping interval, after the motor switch isopened, the fan and pump decelerate but the cut-off valve does not closeimmediately but only when the oil pressure drops 0 below thepredetermined value. Oil flow can continue for a short interval atatomizing pressure, while the rate of air flow is diminishing, thusproviding an overrich mixture which causes smoky operation. The cut-oilvalve after closing does not always remain closed. .There may be amomentary rise of pressure after thevalve closes, causing opening of thesame for an instant, followed by another closing of the valve and soforth, causing a chattering of the valve and emission of spurts of oil.To overcome smoky operation during the starting and stopping intervals,the air inlet shutter is adjusted to admit air at a greater rate butthis, of course,

means that air flow will be at a greater rate than is needed during thenormal running inter-val, and this results in inefficient combustion.

This invention has for its object the provision of a new and better wayto enable efficient combustion to be obtained during the normal runninginterval of each cycle of operation of the 1 Claim. (Cl. 158-28) objectthe provision of a by-pass around thepump, controlled by a valve whichis open when the burner motor starts, and remains open for a certaintime interval, at least long enough for the fan to attain full speed andpreferably somewhat longer, and which opens simultaneously with theopening of the circuit to the burner motor, whereby the pump starts upunloaded and is prevented from building up sufficient pressure to openthe cut-off valve until the full rate of air flow has been establishedand whereby the pump is unloaded simultaneously with the opening of thecircuit to the motor so that an instantaneous cut-off of oil flow to thenozzle occurs before any deceleration of the motor fan and pump occurs.

The invention also has for an object the provision with a pump-unloadingmeans of the kind described of an auxiliary cut-off valve locatedbetween the usual cut-01f valve and the nozzle of the burner and closingand opening with the opening and closing, respectively, of the unloadingvalve, such auxiliary cut-01f valve preferably being of a constructionsuch as not to be adversely afiected by high pressure and not subject tothe chattering action described and preventing flow by gravity headthrough the pump to the nozzle, when the usual high-pressure cutoffvalve leaks as it often does.

The invention will be disclosed with reference to the illustrativeexample of it shown in the accompanying drawings, in which,

Fig. 1 is an exterior elevational view of an oil burner embodyingtheinvention;

Fig. 2 is a sectional plan View takenon the line 2-2 of Fig. 1;

Fig. .3 is a cross sectional view taken on theline 33 of Fig. 1; v

Fig. 4 is afragmentary sectional view showing the-usual cut-off andby-pass valves provided for the fuel pump;

cludes a body casting l (Fig. 1), suitably supported, as by the floorplate 2 and standard 3. This body provides in its upper portion a fanhousing 4, the outlet of which opens into the front end of ahorizontally-disposed cylindrical conduit 6, provided in the lowerportion of the body. Mounted to rotate in this housing 4 is a fan I. Therear end of conduit 3 is closed by a cover 8, which is mounted for easyremoval, as indicated. Fixed to casing l is a tube 9, which, as shown inFig. 2, is located coaxially, and forms a prolongation of the conduit 6,the rear end of the tube communicating with the front end of theconduit. The front end of tube 9 is adapted to be inserted through thewall of the combustion chamber. Tube 9 has fixed to its front end asuitable air director It! and, inside the tube, near the front endthereof, is a turbulator, consisting of a circular series ofangularly-spaced spiral vanes ll, fixed to an annular ring l2, which hassliding engagement with the interior peripheral wall of tube 9. Anoil-atomizing nozzle l3, of the high-oil-pressure-atomizing type, issupported centrally of tube 9 near its front and outlet end. It will beseen that fan I Will force air, which is drawn into its housing 4, in amanner to be later described, through the outlet 5 into conduit 6 andthence forwardly through such conduit and through tube 9, past thespiral vanes I i,

which whirl the air stream, and then to air director l9, which directsthe whirling air stream into the spray of atomized oil emitted from thenozzle 13. The mixture of air and oil, thus produced, is ignited by anelectrical spark, produced between a, pair of electrodes M.

The nozzle l3 and electrodes 14 may be supported in any suitable manner.For example, a pair of rods l5 (Fig. 2) are fixed at one end to ring l2,at diametrically opposite points thereon, and extend rearwardly throughtube 9 into conduit 6 and terminate with ends l6, which are bentoutwardly at right angles and inserted in holes formed in the peripheralwall of the conduit. Fixed to and spanning these rods, is a cross piecell, through which extends the oil-conducting tubular support 18 fornozzle 13. The cross piece ll also has fixed therein two insulatingtubes 19, in which the described electrodes M are supported. The nozzlesupport I8, and insulators [9 are adjustable in cross piece 11, asindicated. By removing cover 8 the ends 16 of rods I5 may be pulled outof their retaining holes and then 'the rods may be drawn rearwardly ofconduit 6 to remove the nozzle l3, electrodes l4 and'the turbulator I I,I2, all in assembled relation.

The electrodes M (Fig. 2) are adapted to be connected by wires 29 to thehigh tension tempnals 2| of a suitable ignition transformer 22 (see alsoFig. 3), which is fixed to and located outside body I with its hightension terminals 21 and insulators 23 projecting through anopening inthe wall of conduit 6 into the interior thereof.

A flexible copper tube 2-4 (Fig. 2) is connected at one end to theoil-conducting nozzle support 18 and extends rearwardly through tube!and conduit 6, emerging therefrom through a passage in cover 8, asindicated in Fig. 1, for connection to the oil-supply means, to bedescribed. I

The fuel-feeding means for the pressureatomizing nozzle 13- includes asuitable positivelyacting pump, indicated generally at 25, the usualnozzle cut-off and pressure-regulating or by-pass valves, which in thiscase are mounted in an extension 29 of the pump casing, and apump-unloading valve and auxiliary nozzle cut-off valve 4 to be laterdescribed in detail. The pump with the cut-oif and by-pass valves may,for example, be constructed as disclosed in Wahlmark Patent No.2,309,683, to which reference is made for a more complete disclosure, ifnecessary or desired. This unit (Fig. 3) is bolted to the outer end faceof a bracket 21, which is disposed in spaced parallel relation with oneend wall 28 of the fan housing and is integrally connected thereto bytwo side arms 29. The pump unit is supported with its driving shaft 33in substantially coaxial relation with the fan I. Shaft 30 is connectedby a flexible coupling 3! to the hub 32 of fan 1, which is fixed to theshaft 33 of an electric motor 34 secured as indicated to one side of thefan housing.

The driving elements for the oil pump (Fig. 3) extend out of the fanhousing through a large hole 35 which forms the air inlet to fan i.Coopcrating with this inlet is a shutter 36, which is movable to adjustthe effective area of the fan inlet and thus the rate at which air issupplied to the oil spray produced by nozzle l3. This shutter has acentral opening through which shaft 39 passes. The shutter has threadedengagement with an adjusting screw 31, which is rotatably supported atits inner end in wall 28 and at its outer end in bracket 2'1. A spring38, acting between this bracket and a collar 39 on the screw, forces thelatter to the left and holds a shoulder on the screw engaged with wall28. This spring also tends to prevent accidental rotation of the screw.A casing 40 encases the shutter, screw and clutch and is provided withair inlet slots 4! of adequate aggregate area. The shutter is preventedfrom rotating by a rod 42, with which it is slidably engaged, this rodbeing fixed at its outer end in bracket 21.

The usual provisions for regulation of oil pressure are shown in Fig. 4.The passages 43 and 44 respectively connect the outlet and inlet sidesof the oil pump to a cylindrical bore 45 at longitudinally spacedlocations. Fixed in this bore, between such locations is a sleeve 45.The ends of bore are closed by plugs 41 and 48, each having its innerend spaced from the adjacent end of sleeve 46, thereby forming chambers49 and 59, respectively communicating with outlet and inlet passages 43and 44. Slidably mounted in sleeve #6 is a hollow piston 5i, havingfixed to its outer and closed end a. valve 52, adapted to engage a seat53 on closure plug 41 and close off communication between chamber 49 andan outlet passage 54 in plug 47. A spring 53 acts between the closed endof piston 51 and a seat 56 to urge valve 52 into engagement with itsseat 53, whereby outflow of oil to nozzle I3 is pre-. vented. Seat 55 isadjustable by means of a screw 51, threaded into closure plug 48 and,normally covered and concealed by a cap nut 58, which is threaded on ahollow hub on plug 48 The valve 52 willbe opened by pressure of the oilon the outer end face of piston 5|, when such pressure reaches apredetermined minimum value, which may for example be 95 p. s. i. Whenthe pressure of the pumped oil reaches. a somewhat higher predeterminedpressure, say for example,

p. s. some oil will be by-Dassed back to.

the suction side of the pump in order to. main-. tam the pressure of theoil supplied to nozzle I 3 substantially constant. A hole 59 in theperiph eral wall of piston 5! will move into communication with acircumferential groove 6.3 in the interior peripheral wall of sleeve.46, when the. oil pressure rises to the second predetermined value,

and some oil from chamber 49 can then flow through a passage 6| insleeve 46 into groove 60 and thence through hole 59 to the interior ofpiston 51, which constantly communicates with chamber 50 and thus withthe inlet side of the oil pump.

The inlet of the pump is connected to a suction pipe 52, which as shownin Fig. 1 includes, intermediate its ends, a T 52, the side branch ofwhich is connected by a pipe 63 to the unloading valve to be described.The described outlet chamber i9 has a second outlet 54 which isconnected by a pipe 65 to the unloading valve. The outlet 5d, controlledby the usual nozzle cut-off valve 52, is connected by a pipe 65 to theinlet of the auxiliary nozzle cut-oi? valve to be described and theoutlet of the latter is connected to the described nozzle supply pipe24.

The unloadin valve and auxiliary nozzle cutoff valve will next bedescribed with reference to Figs. 5, 6 and 7. These valves are combinedin a single tapered plug 61, which is mounted in a casing 58 to turnabout its axis through a small angle. Casing 68 has two ports 69 and Hitherein, which are respectively connected by the described pipes 63 and55 to the inlet and outlet of the fuel pump. These two parts areconnected, when valve plug 6? is in the illustrated and rest position,by a passage 'il in the plug. The latter, at a different level isprovided with a diametrical passage 12, which is adapted when the plugis moved to the other of its extreme positions, to interconnect twoports 13 and id in the casing 68, which ports are respectively connectedby the pipes 66 and 24 to the outlet of the usual nozzle cut-off valve52 and to the atomizing nozzle it. The casing 58 is extended beyond thelarge end of plug 6'! to form a chamber 15 having a removable wall orcover 16 through which access is had for the assembly of parts. A springI? acts between cover 16 and the adjacent end of plug 5! to press thelatter into close engagement with its seat in the casing. The turningmovement of the valve plug 67 is limited by the abutment of a pin 78 onthe plug with either of two stop pins 15 or as, fixed to the casing.When pin '18 abuts stop l9, as shown, the valve plug 61 is positioned sothat the ports 69 and it are connected by the valve passage ll wherebythe inlet and outlet sides of the fuel. pump are interconnected tounload the pump; also the valve passage 12 is positioned as shown inFig. 7 to prevent communicatlon between the ports 13 and Hi whereby .toprevent how of oil to nozzle [3. When the valve plug is turned until pin18 abuts stop 80, one end of the passage H will be moved out ofcommunication with port 69 to block oil communication between the inletand outlet sides of the fuel pump and enable it to build up pressure toopen the usual cut-off valve 52 and by-pass valve 59; also the passage12 will be so positioned as to interconnect ports 13 and M and allow oilto flow to the atomizing nozzle 1 3.

For turning the valve plu 67 a solenoid 8| is provided operable, whenenergized, to move its the valve-actuating solenoid 8i.

member is of non-magnetic material. The solenoid is encased by a twopart casing 86 of magnetic material, the two parts of which are clampedbetween shoulders 81 and 88 on the members 8d and 85. The outer end ofmember 85 is screw threaded into a tapped hole in a side wall of thedescribed chamber 75. The plunger 82 is of hexagonal cross sectionalshape and has a cylindrical extension 89 which passes through thelast-named end of member 85 into chamber 15, where it terminates with aflattened part having an upstanding pin 96. The end face of valve plug6! that lies in chamber l5 has a similar upstanding pin 9! which isconnected to pin 9!] by a link 92. In assembling the parts, the valveplug 61 is first inserted into its casing 68; then member 85 is screwedinto the side outlet of the casing with the extension 89 projecting intochamber 15; then the extension is turned, if necessary, to position pinproperly for connection to pin it I; then link 92 is applied to connectthese two pins and is held in place as indicated; then spring ll isplaced in its seat in the valve plug; and the cover 56 is applied andfastened in place by the screws 93.

The solenoid-controlled valve described is mounted in any suitable wayon the burner, as for example as indicated in Figs. 1, 2 and 3, by meansof a clamp 94 and screws 95 which hold the casing 86 to the lower partof body casting I.

The energization of solenoid BI is made to occur a predetermined timeafter the burner motor 34 is energized and continues until this motor isdeenergized. An exemplary means for effecting these results is showndiagrammatically in Fig. 8. The burner motor 35 and the primary 96 oftransformer 22 are connected in parallel in a circuit comprising Wires9?, 98 and 99 and a control switch at of any suitable form and usuallyactuated by a thermostat. No attempt has been made to show the detailsof the motor control and the various safety devices commonly employedtherewith. The diagram is intended merely to show the relationshipbetween the burner motor 34 and The latter is arranged in a circuit fromthe wires 98 and 59 which circuit is controlled by a time switch, hereinexemplified by a bimetallic member iii! having a contact Hi2 adapted tobe moved, when member Iii! is sufiiciently heated, into engagement witha stationary con-tact 63. The member I0! is connected by a wire 104 towire $9; the contact lot is connected by a wire 1 35 to one terminal ofsolenoid 8|; and the other terminal of the latter is connected by a wireits to wire 98. An electric heating coil Ill! is provided for heatingthe thermostat member [ill and has its terminals connected to wires m4and H36 and thus in parallel with the burner motor 34 to be energizedwhenever the motor is energized. This heating device is arranged toactuate the member IOI to cause engagement of the contacts m2 and I03 ina predetermined time, say for example, five seconds, which time is longenough to enable the burner fan 7 to attain full speed and establishnormal air flow past the atomizing nozzle 1 3.

In operation, when the switch IE6 is closed to start the burner motor 3dand energize the ignition transformer 22, the solenoid 8| is notimmediately energized and the valve plug 6'! occupies the positionillustrated, whereby the inlet and outlet sides-of the fuel pump areinterconnected and communication between the ports 73 and 14 isprevented to cut ofiv flow to the atomizing nozzle 53, independently ofthe usual cut-off valve 52.

The pump is therefore initially unloaded and can be accelerated rapidly,even by a small motor having low starting torque. After the motor hasoperated for the desired time, which preferably should be long enoughfor the fan I to attain full speed and to get the air flowing past theatomizing nozzle 13 at the normal rate, the switch |n2 |ca will beclosed to cause energization of the solenoid 8i and movement of thevalve plug 61 into its other position, in which fiow to nozzle I3 ispermitted and the pump unloading by-pass, comprising pipe $3, port 59,valve passage H, port it] and pipe 65, is closed. The fuel pump 25rapidly builds up oil pressure until the cut-off valve 52 opens andallows oil to flow to the nozzle I3 .to be atomized thereby and mixedwith the air stream, which may be and preferably is moving at the fullrate established to secure good combustion. Operation of the burnercontinues until switch Ills is opened, whereupon the burner motor 34 andsolenoid 8| are simultaneously deenergized. This results in aninstantaneous cutting off of oil flow to the nozzle 13 by the auxiliarycut-ofi valve at the very start of the deceleration interval and beforethe pump 25 has decreased in speed enough to cause closure of the usualcut-off valve 52. It also causes unloading of the oil pump 25. While theunloading of the pump should cause quick closure of the usual cut-oil"valve 52, this valve does not always close tightly. It is subjected tohigh pressure and likely to become leaky after it has been in use forsome time. If this usual cut-off valve does leak, fuel can sometimesflow by gravity head through the gears of the oil pump to the nozzle 13,issuing in unatomized condition as drip. The auxiliary cut-off valve canbe made to fit tightly and is not adversely influenced by high pressureand less likely to become leaky after long use. The auxiliary cut-offvalve provides insurance against oil flow to the nozzle at unwantedtimes.

The invention therefore provides means for preventing the flow of anyoil during any part of the acceleration and deceleration intervals ofoperation of a pressure-atomizing oil burner. Oil can be admitted onlyafter the fan has acquired full speed and has had time to establish airflow at the full rate past the atomizing nozzle. Such rate of air flowcan therefore be made that which is necessary for the most efilcientcombustion without any possibility of smoky operation during theintervals in the cycle of operation of the burner when the fan isaccelerating or decelerating.

What is claimed is:

In an oil burner havin a pressure-atomizing nozzle, an oil-supply pump,an air-supply fan, an electric motor for driving the pump and fan, and apressure-regulating valve connected to the outlet of the pump andclosing the same until the pump has built up a predetermined highatomizing pressure; a second valve comprising a casing having first andsecond pairs of ports and an element movable in said casing betweenfirst and second positions and having first and second valve passages torespectively control said first and second pairs of ports, a conduitconnecting the first-named valve to one port of the first pair, aconduit connecting the other port of the first pair to said nozzle,conduits connecting the ports of the second pair one to the inlet andone to the outlet side of said pump, said element when in its firstposition having its second valve passage positioned to interconnect thesecond pair of ports and its first valve passage positioned to preventcommunication between the first pair of ports and when in its secondposition having its first valve passage positioned to connect the firstpair of ports and its second valve passage positioned to preventcommunication between the second pair of ports, biasing means forholding the valve element in its first position, electrical means formoving the valve element against its biasing means from its first to itssecond position, an electrical circuit for said motor, an electricalcircuit for said electrical means connected to the first-named circuit,and a switch for controlling the second circuit, said switch being openwhen the motor is deenergized, and actuating means for said switchinitiated simultaneously with the energization of said motor andoperable in a predetermined time interval to close said switch and causeenergization of said electrical means.

JOSEPH A. LOGAN. EUGENE V. LAVALLEE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,263,654 Doble Apr. 28, 1918 2,145,404 Osborne Jan. 31, 19392,489,823 Senninger Nov. 29, 1949 2,608,999 Wheeler Sept. 2, 1952

